package com.code.upload.utils;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.math.BigDecimal;
import java.math.MathContext;
import java.util.ArrayList;

/*** * 对图片进行操作 * * @author chenzheng_java * @since 2011/7/29 * */
public class ImageHelper {
    private static ImageHelper imageHelper = null;

    public static ImageHelper getImageImageHelperHelper() {
        if (imageHelper == null) {
            imageHelper = new ImageHelper();
        }
        return imageHelper;
    }

    public static void main(String[] args) {
        scaleImageWithParams("E:\\1.png", "E:\\2.png", 1000, 1000, true, "PNG");
    }

    /*** * 按指定的比例缩放图片 * * @param sourceImagePath * 源地址 * @param destinationPath * 改变大小后图片的地址 * @param scale * 缩放比例，如1.2 */
    public static void scaleImage(String sourceImagePath, String destinationPath, double scale, String format) {
        File file = new File(sourceImagePath);
        BufferedImage bufferedImage;
        try {
            bufferedImage = ImageIO.read(file);
            int width = bufferedImage.getWidth();
            int height = bufferedImage.getHeight();
            width = parseDoubleToInt(width * scale);
            height = parseDoubleToInt(height * scale);
            Image image = bufferedImage.getScaledInstance(width, height, Image.SCALE_SMOOTH);
            BufferedImage outputImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
            Graphics graphics = outputImage.getGraphics();
            graphics.drawImage(image, 0, 0, null);
            graphics.dispose();
            ImageIO.write(outputImage, format, new File(destinationPath));
        } catch (IOException e) {
            System.out.println("scaleImage方法压缩图片时出错了");
            e.printStackTrace();
        }
    }

    /*** * 将图片缩放到指定的高度或者宽度 * @param sourceImagePath 图片源地址 * @param destinationPath 压缩完图片的地址 * @param width 缩放后的宽度 * @param height 缩放后的高度 * @param auto 是否自动保持图片的原高宽比例 * @param format 图图片格式 例如 jpg */
    public static void scaleImageWithParams(String sourceImagePath, String destinationPath, int width, int height, boolean auto, String format) {
        try {
            File file = new File(sourceImagePath);
            BufferedImage bufferedImage = null;
            bufferedImage = ImageIO.read(file);
            if (auto) {
                ArrayList<Integer> paramsArrayList = getAutoWidthAndHeight(bufferedImage, width, height);
                width = paramsArrayList.get(0);
                height = paramsArrayList.get(1);
                System.out.println("自动调整比例，width=" + width + " height=" + height);
            }
            Image image = bufferedImage.getScaledInstance(width, height, Image.SCALE_DEFAULT);
            BufferedImage outputImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
            Graphics graphics = outputImage.getGraphics();
            graphics.drawImage(image, 0, 0, null);
            graphics.dispose();
            ImageIO.write(outputImage, format, new File(destinationPath));
        } catch (Exception e) {
            System.out.println("scaleImageWithParams方法压缩图片时出错了");
            e.printStackTrace();
        }
    }

    /**
     * 将double类型的数据转换为int，四舍五入原则 * * @param sourceDouble * @retur
     */
    private static int parseDoubleToInt(double sourceDouble) {
        int result = 0;
        result = (int) sourceDouble;
        return result;
    }

    /*** * * @param bufferedImage 要缩放的图片对象 * @param width_scale 要缩放到的宽度 * @param height_scale 要缩放到的高度 * @return 一个集合，第一个元素为宽度，第二个元素为高度 */
    private static ArrayList<Integer> getAutoWidthAndHeight(BufferedImage bufferedImage, int width_scale, int height_scale) {
        ArrayList<Integer> arrayList = new ArrayList<Integer>();
        int width = bufferedImage.getWidth();
        int height = bufferedImage.getHeight();
        double scale_w = getDot2Decimal(width_scale, width);
        System.out.println("getAutoWidthAndHeight width=" + width + "scale_w=" + scale_w);
        double scale_h = getDot2Decimal(height_scale, height);
        if (scale_w < scale_h) {
            arrayList.add(parseDoubleToInt(scale_w * width));
            arrayList.add(parseDoubleToInt(scale_w * height));
        } else {
            arrayList.add(parseDoubleToInt(scale_h * width));
            arrayList.add(parseDoubleToInt(scale_h * height));
        }
        return arrayList;
    }

    /*** * 返回两个数a/b的小数点后三位的表示 * @param a * @param b * @return */
    public static double getDot2Decimal(int a, int b) {
        BigDecimal bigDecimal_1 = new BigDecimal(a);
        BigDecimal bigDecimal_2 = new BigDecimal(b);
        BigDecimal bigDecimal_result = bigDecimal_1.divide(bigDecimal_2, new MathContext(4));
        Double double1 = new Double(bigDecimal_result.toString());
        System.out.println("相除后的double为：" + double1);
        return double1;
    }
}